The present invention relates to a polarizing beam splitter, a polarizing beam converter and a liquid crystal display for converting the non-polarized light from an illumination source to linearly polarized light.
In recent years, there have been remarkable advances in liquid crystal display technology, especially in the provision of a color liquid crystal display apparatus, so that various kinds of color liquid display apparatus now being provided are found to have a display quality higher than that of a CRT display apparatus. However, since the light produced by a light source is non-polarized light in conventional systems, as in the case of TN-type liquid crystal devices, almost half of the incident light is absorbed by the polarizing plate arranged at the incident side of the display device, so that the efficiency of light utilization is low and the display images are not as bright as desired. There is also a problem that the electric power consumption increases when an attempt is made to obtain brighter display images.
In recent systems, the use of polarizing beam converters using inorganic materials has been proposed in order to increase the efficiency of light utilization (Japanese Patent Application Laid-Open Number 5-241103 1993)). The polarizing beam splitter or the polarizing beam converter used in the conventional projection type liquid crystal display apparatus, which is formed by building multiple dielectric layers on a glass plate cut at 45.degree., has a large angular dependency. And furthermore, since glass materials are used, the display apparatus is heavy and its cost is high.